A Gigabit Passive Optical Network (GPON) provides a network of large bandwidth to subscribers to execute various multi-protocols. A GPON, which is one Fiber-To-The-Home (FTTH) service standardized by the International Telecommunications Union-Telecommunication Standardization Sector (ITU-T), has a structure where a plurality of optical network terminals (ONTs, or also referred to as optical network units (ONUs)) are connected to a single optical line terminal (OLT) through a passive element by a Point-to-Multipoint (PTM) method.
An OLT, which is a multi-service unit for connecting an optical subscriber network to another system, may be any one of a Service Interface and Protocol Processing (SIPP) unit, a CATV, a transmitter, a network manager and the like. An OLT or ONU is a network terminator which can connect to a Fiber-To-The-User (FTTU) system which is one kind of next-generation network.